A magnetic recording medium basically consists of a non-magnetic base made of a material such as a polyester film, and an overlying magnetic layer principally made of ferromagnetic particles and a binder. Today, ferromagnetic metal particles having high saturation magnetization and coercive force are used for the purpose of providing increased magnetic recording density and reproduction output. Ferromagnetic metal particles have good magnetic properties, but because of their high saturation magnetization (.sigma.s), the interaction between the individual particles is great, a dispersion of the particles is not easily formed, and a dispersion once formed does not remain stable for a sufficient period of time. As a further disadvantage, ferromagnetic metal particles of this type are inherently easily oxidized, so their magnetic properties are more easily impaired with time than oxide magnetic particles. For a magnetic layer containing ferromagnetic metal particles, improvement in the recording density is given the top priority, so the need for shorter recording wavelength and smaller loss in spacing with the head unavoidably requires a smoother tape surface than that of a magnetic layer containing oxide magnetic particles. However, as the tape surface is made smoother, the area of contact with the tape transport system increases and hence the friction coefficient is increased, whereas the durability of the tape is decreased. Because of these disadvantages, the magnetic recording medium obtained often has poor magnetic properties and electro-magnetic conversion characteristics, as well as poor running property and low durability.
Conventionally known vinyl chloride/vinyl acetate resins, polyurethane resins, cellulosic resins, polyester resins and mixtures thereof form a good dispersion of magnetic particles and can be stored for an extended period, as disclosed in Japanese Patent Publication Nos. 19282/64, 5349/65 and 22063/72, and Japanese Patent Application (OPI) Nos. 51704/78, 51705/78, 51706/78, 51707/78, 51708/78 and 84705/79 (the term "OPI" as used herein refers to a "published unexamined Japanese patent application"). However, they do not always have satisfactory running property and durability.